This invention relates to an electrofusion method of producing a corrosion-resistant refractory material which comprises as its major component a boron aluminum oxide phase.
In furnaces for melting glass compositions of the type characterized by comprising boric oxide B.sub.2 O.sub.3 as an essential component and typified by E-glass which is in large use as glass fiber, usually use is made of mullite brick or silica brick as a refractory material with which the melt or vapor emitted by the melt comes into direct contact. A problem in this regard is that the refractory material suffers a significant corrosion due to the presence of boric oxide in the melt and vapor. This problem is not specific to glass industries but is encountered also in other fields where there is the need of treating B.sub.2 O.sub.3 -containing materials in the molten state.
U.S. Pat. No. 2,118,143 shows a refractory material composed fundamentally of about 65-90% of Al.sub.2 O.sub.3 and about 35-10% B.sub.2 O.sub.3 and containing a substantial proportion of crystalline boro-aluminate which is said to have the formula 3Al.sub.2 O.sub.3.B.sub.2 O.sub.3.
Also, the existence of a crystalline bore-aluminate phase expressed by the formula 9Al.sub.2 O.sub.3.2B.sub.2 O.sub.3 is known.